1. Field of the Invention
The present invention relates generally to a wireless packet data communication system, and in particular, to a packet data generating method and apparatus for supporting the transmission of signaling and control information for multiple services.
2. Description of the Related Art
Typically, the CDMA (Code Division Multiple Access) has evolved from the 2nd generation (2G) standards focusing on the voice service to the 3rd generation (3G) CDMA standards (CDMA2000) that provide high-speed data service as well as the voice service. The 3G CDMA mobile communication system supports data rates of up to 3 Mbps (Mega bit per second). The 3G CDMA can transmit more data than the 2G CDMA mobile communication system that supports 9.6 kbps or 14.4 kbps. This data transmission capability enables the provisioning of multiple services including high-quality voice service, transmission of moving pictures, Internet browsing, etc.
In the first developed CDMA2000 mobile communication system (CDMA2000 1× system), packet data is transmitted mainly on a supplemental channel (SCH), but voice or signaling information requiring high reliability is to be transmitted on a fundamental channel (FCH) or dedicated control channel (DCCH) because the FCH and DCCH are designed to have a better quality.
An advanced 3G CDMA mobile communication system proposed to simultaneously support voice service and high-speed packet data service, CDMA2000 1×EV-DV (Evolution-Data and Voice) uses a packet data channel (PDCH) to more stably deliver voice and packets at a higher rate. The PDCH, having a channel quality as good as the FCH or DCCH, can deliver information requiring a high transmission probability, for example, signaling information for call control and RLP (Radio Link Protocol) control in CDMA2000 1×EV-DV, along with voice and packet data.
In the CDMA2000 1× and CDMA2000 1×EV-DV systems, the MAC (Media Access Control) layer uses a plurality of MuxPDU (Multiplex sub-layer Protocol Data Unit) types to support a variety of physical channel types. The MuxPDU Types allow MuxPDUs to be generated through the multiplexing of various services.
Conventional PDU generation methods define some available multiplexing methods. Information about the multiplexing method used is written in the header of a PDU. Especially in a PDU for the FCH, signaling traffic and non-signaling traffic (primary and secondary traffic) can be multiplexed only in the methods defined by the standards. At most, the three services, that is, the signaling traffic, the primary traffic and the secondary traffic, can be multiplexed in one PDU.
Along with the recent diverse user demands, provisioning of multiple services through an identical connection has emerged as a significant issue. As described before, however, since up to three types of services can be multiplexed in the conventional PDU generation methods, user-demanded various types of services cannot be supported. Moreover, the multiplexing is available only in the predefined methods, thereby decreasing efficiency in transmitting data of a variable length.